package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisWorker redisWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();


    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);

    private class VoucherOrderHandler implements Runnable {
            String queueName = "stream.orders";
        @Override
        public void run() {
            while (true) {
                try {
                    //1.获取消息队列中的订单 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS streams.order >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofMillis(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    //2.判断消息是否获取成功
                    if (list == null || list.isEmpty()) {
                        //2.1.如果获取失败 没有消息，继续下一次循环
                        continue;
                    }
//                   3. 解析消息队列中的消息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //4.如果获取成功 就下单
                    handleVoucherOrder(voucherOrder);
                    //5.ACK确认 SACK streams.order g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    //1.获取pending-list中的订单 XREADGROUP GROUP g1 c1 COUNT 1  STREAMS streams.order 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    //2.判断消息是否获取成功
                    if (list == null || list.isEmpty()) {
                        //2.1.如果获取失败 pending-list没有异常消息，结束循环
                        break;
                    }
//                   3. 解析消息队列中的消息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //4.如果获取成功 就下单
                    handleVoucherOrder(voucherOrder);
                    //5.ACK确认 SACK streams.order g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list订单异常", e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException interruptedException) {
                        interruptedException.printStackTrace();
                    }
                }
            }
        }
    }

    /*private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    private class VoucherOrderHandler implements Runnable{
        @Override
        public void run() {
            while (true){
                try {
                    //1.获取队列中的订单
                    VoucherOrder voucherOrder = orderTasks.take();
//                2.创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                }
            }
        }
    }*/

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        //判断是否获取锁成功
        if (!isLock) {
            //获取锁失败
            log.error("不允许重复下单");
            return;
        }

        //获取代理对象（事务）
        try {
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            //释放锁
            lock.unlock();
        }
    }

    private IVoucherOrderService proxy;

    @Override
    public Result seckillVoucher(Long voucherId) {

        Long userId = UserHolder.getUser().getId();

        Long orderId = redisWorker.nextId("order");


//        1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString(),
                orderId.toString()
        );
        int r = result.intValue();

//        2.判断结果是否为0
        if (r != 0) {
//        2.1.不为0
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //
        proxy = (IVoucherOrderService) AopContext.currentProxy();

//        3.返回订单id
        return Result.ok(orderId);


    }

 /*   @Override
    public Result seckillVoucher(Long voucherId) {

        Long userId = UserHolder.getUser().getId();

//        1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString()
        );
        int r = result.intValue();

//        2.判断结果是否为0
        if (r != 0) {
//        2.1.不为0
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
//        2.2.为0，有购买资格，把下单信息保存到阻塞对列当中
        VoucherOrder voucherOrder = new VoucherOrder();

        Long orderId = redisWorker.nextId("order");
//        2.3设置订单号
        voucherOrder.setId(orderId);
//        2.4设置user id
        voucherOrder.setUserId(userId);
//        2.5设置订单编号
        voucherOrder.setVoucherId(voucherId);

//        TODO 保存阻塞队列
//        创建阻塞队列
        orderTasks.add(voucherOrder);

        proxy = (IVoucherOrderService) AopContext.currentProxy();

//        3.返回订单id
        return Result.ok(orderId);


    }*/

   /* @Override
    public Result seckillVoucher(Long voucherId) {
        // 1.查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2.判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            return Result.fail("秒杀尚未开始");
        }

        // 3.判断秒杀是否已经结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            return Result.fail("秒杀已经结束");
        }
        //4.判断库存是否充足
        if (voucher.getStock() < 1) {
            return Result.fail("库存不足");
        }
        Long userId = UserHolder.getUser().getId();

        //创建锁对象

//        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        //判断是否获取锁成功
        if (!isLock){
            //获取锁失败
            return Result.fail("一个人只允许下一单");
        }

        //获取代理对象（事务）
        try {
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }


    }*/


    @Transactional
    @Override
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //5 一人一单
        Long userId = voucherOrder.getUserId();
//       5.1 查询订单
        int count = query()
                .eq("user_id", userId)
                .eq("voucher_id", voucherOrder.getVoucherId())
                .count();
        //判断是否存在
        if (count > 0) {
//            用户已经购买过
            log.error("该用户已经购买过了");
            return;
        }
        // 5.扣减库存
        boolean success = seckillVoucherService
                .update().setSql("stock = stock - 1")
                .eq("voucher_id", voucherOrder.getVoucherId())
                .gt("stock", 0) //加上乐观锁 CAS
                .update();
        if (!success) {
            log.error("库存不足");
            return;
        }
//        写入数据库
        save(voucherOrder);

    }
}
